Found in a 1947 publication, this circuit uses 4 parallel/push-pull tuber in the output stage. The circuit employs dual power supply with two rectifier tubes.
This circuit was found in an American magazine in 1978. It activates a relay when the speed of a...
This second-order low-pass Salen-Key filter was obtained from an American 1980s documentation. Formulas...
The circuit shown in figure 1 generates an intermittent tone in a piezoelectric transducer when...